This invention relates to interlocked stiffened panels and more particularly to aluminum extruded panels suitable for use as aircraft landing mats.
In the building of temporary air fields, landing mats or panels, which can be locked together with the minimum of tools, are used. The prior panels required a watertight construction, and thus included significant welding. The strength of such panels was provided by a truss structure. However, such panels have the problem of being heavy and bulky. This results in high volume that does not permit maximum transportation pay load. For example, if the thickness can be reduced from two to one inch, this results in double the pay load. Thus, there is a great need for a slim yet strong mat or panel that lends itself to economic transportation and quick and efficient assembly.
Examples of floors and landing mats are provided in the references. For example, U.S. Pat. No. 3,635,130 discloses an improved landing mat installation and the like comprised of a plurality of removably interlocked panels, wherein the joints formed by various marginal edges of the panels are provided with improved cooperating locking and sealing means that advantageously inhibit the penetration of water and the like through the joints as well as facilitating the installation and dismantlement of the panels making up the landing mat installation.
U.S. Pat. No. 4,440,363 discloses a landing mat for compacted terrain formed by assembling a multiplicity of mat elements in contiguous relationship. Each of these elements has a rectangular plan configuration and is formed along its longitudinal edges with downwardly bent flanges, and between these flanges, with flattened corrugations forming longitudinal ribs perpendicular to the planar upper surface of the element. Stabilizing plates can extend transversely to the ribs and flanges and can have upwardly open slots snugly receiving the ribs. Clips bridging contiguous edges of adjoining elements are fitted into elongated windows spaced inwardly of these edges to hold the elements together and an edge member, likewise having a flattened-corrugation rib, is fixed along one edge of the mat and has downwardly turned tongues fitted into the window of the elements along the latter edge.
U.S. Pat. No. 2,737,093 discloses a metal mat adapted to be laid side by side with like mats to form an airfield deck, the mat comprising a ground plate having corrugations extending lengthwise thereof and forming laterally spaced troughs, a deck plate secured to the top of the ground plate between the troughs, cooperative connecting means on the opposite sides of the deck plate for connection to the deck plate of an adjoining mat to interlock the mats, the deck plate being provided with a plurality of longitudinally spaced openings above troughs of the ground plate, vertical struts extending downward from the deck plate to the bottoms of the troughs for spacing the deck plate and the bottoms of the troughs apart when the mat is supporting a load, the struts extending transversely of the troughs with their upper ends connected by integral bends to the sides of the openings, and a trough-like connecting member slidably disposed in one end of a trough and adapted to be slid part way out of the trough and into an aligned trough of another mat to connect the adjoining ends of the two mats, the upper part of the connecting member being provided with a bendable ear, and the deck plate being provided with an opening for receiving the ear when it is bent upward to lock the connecting member against longitudinal movement.
U.S. Pat. No. 3,372,466 discloses a continuous process for manufacturing a metal landing mat comprising rolling two identical hot slabs simultaneously by opposed pairs of pressurized rollers to form hot identical waffle-like half mats having one corrugated side and one flat side, and arranged to discharge from the rollers with their corrugated sides inward; feeding the half mats into coordinated contact so that the corrugations of one half mat contact the corrugations of its companion half mat in abutting relationship; and pressure rolling the hot half mats to weld the opposed half mats at all points of contact.
U.S. Pat. No. 2,294,550 discloses a plurality of metallic plates adapted for rapid attachment and detachment to form a substantially horizontal portable deck capable of sustaining superposed loads, each of the plates having a series of aligned spaced openings inwardly of an edge thereof, and being provided outwardly of the openings with a series of aligned spaced downwardly-projecting lugs adapted to align with, and extend through, the openings of a similarly formed and adjacently disposed plate, each of the lugs comprising a shank and an enlarged head portion, the openings in the plates being substantially larger than the enlarged head portions of the lugs thereof whereby, upon disposing the lugs in the the openings and subjecting the plates to relative longitudinal movement, the enlarged head portions of the lugs of one of the plates are disposed beneath the bottoms of the similarly formed and adjacently disposed plate to thereby effect an interlock.
U.S. Pat. No. 3,319,543 discloses a structural unit comprising elongated plate-like top and bottom members joined by spaced apart longitudinally extending web members which run from end-to-end of the top and bottom members. The top and bottom members and the web members define a plurality of channels when viewed in transverse cross-section. A plurality of tubular elements are provided and each of the tubular elements are dimensioned to fit closely but slidably into one of the channels. The length of the tubular elements is a minor fraction of the length of the unit, the tubular elements being disposed within the channels with an end of each of the channels being coextensive with the end of one of the web members. The end of the channels and the end of the web members are welded together. The end parts of the top and bottom members and the tubular elements are beveled whereby the top of the tubular elements and the top and bottom parts of the web members are exposed, and an elongated end coupling element is received on the beveled surfaces. The coupling element is welded to the top and bottom members, the top and bottom parts of the tubular elements, and the top 30 and bottom parts of the web members.
U.S. Pat. No. 3,385,182 discloses metallic load bearing plank for use with other similar planks in assembly of a horizontally disposed platform for movement of vehicles over uneven terrain, for aircraft landing mats, and the like, in which a plurality of load bearing planks are interlocked to prevent substantial vertical and horizontal movement relative to each other while providing for easy assembly and permitting normal expansion and contraction due to temperature change. The metallic load bearing plank comprises an elongated unitary body portion having an upper substantially flat slab surface and a lower substantially flat slab surface, which upper and lower slab surfaces are interconnected by vertically disposed load bearing ribs, continuous female interconnecting means formed integral with the body portion of the plank means and extending along one longitudinal side of the body portion. A continuous male interconnecting means is formed integral with the body portion of the plank means and extends along the remaining longitudinal side of the body portion. The continuous female and male interconnecting means is complementary with male and female inter connecting means respectively on similar metallic load bearing planks. The continuous female interconnecting means defines a vertically disposed pocket means opening upwardly in a direction transverse to the upper slab surface along the one longitudinal side of the body portion. A horizontally disposed pocket means opening is disposed in a direction substantially parallel to the lower slab surface and spaced from the lower slab surface in the direction of the upper slab surface.
U.S. Pat. No. 3,385,183 discloses a modular load bearing platform comprising a multiplicity of similar rectangular load bearing planks arranged in a number of parallel rows each containing several planks disposed in end-to-end relation, each plank including first and second end connecting means along its end edges, respectively, and first and second side connecting means along its side edges, respectively. The first and second end connecting means has complementary shapes and is adapted for releasably interlocking engagement with the end connecting means on adjacent planks in the platform. The several planks in each plank row are releasably joined in end-to-end relation by interlocking engagement of the first end connecting means on each plank with the second end connecting means on an adjacent plank in the respective row.
U.S. Pat. No. 3,538,819 discloses a novel and improved assembly of matting elements that provide a suitable structural planar surface for aircraft takeoff and landing operations. The component mats or modules of the assembly are interconnected and interlocked to restrict relative movement therebetween by providing each mat with one or more locking pins that are disposed between upper and lower planar surfaces of each mat and slide between a nonlocking position where the pin is fully withdrawn in the mat and a locking position where the pin projects outwardly from its associated mat and engages an adjoining mat.
U.S. Pat. No. 4,373,306 discloses a structural element, such as a section of a duckboard (e.g. a landing mat) to be removably fastened to a similar section, has one or more edges provided with male coupling formations adapted to be converted into complementary female formations by breaking off a projecting part thereof. The projecting part is generally T-shaped, with its frangible stem rising from the bottom of a preferably dovetail-shaped recess. Such an element can therefore be readily joined to another element having a mortise complementary to the head of the T or a tenon complementary to the recess.
U.S. Pat. No. 6,007,271 discloses a mat used as a ground engagement platform for supporting heavy equipment or as a road surface for supporting vehicular traffic. The use is intended to be temporary, with the mats being reusable. The mat, in its basic construction, includes a flat plate-like structure having a thickness and planar extent and an opening defined in the flat plate-like structure which extends in the thickness direction and is dimensioned to receive a lifting device for lifting and transporting the mat.
U.S. Pat. No. 4,488,833 discloses a transportable modular assault vehicle water egress and bridge access/egress surfacing or trackway system wherein a plurality of rectangularly shaped planks or sections are joined by flexible hinge members and can be folded accordion fashion and suspended in a container for storing, transporting and rapidly deploying to provide a surfacing upon the shores or banks of bodies of water for the access and egress of military vehicles into and out of bodies of water during military operations.
U.S. Pat. No. 3,984,961 discloses a solution to the problem of distortion and deformation of the floor of a light weight shipping container. Heretofore, relatively heavy loading of lightweight shipping containers has caused the floor thereof to deflect sufficiently to distort the side walls and end walls of the container and often permanently deform the floor. In practicing the present invention, the floor boards adjacent the side walls of the container are modified so as to increase the resistance thereof to shear loads and thus minimize deflection.
U.S. Pat. No. 6,733,206 discloses a ground cover mat which includes a first end interlock at a first end of the body which is adapted to interlock with a second end interlock at a second end of a like body. A second end interlock is provided at the second end of the body which is adapted to interlock with the first end interlock at a first end of a like body. A first side interlock is provided at a first side of the body which is adapted to interlock with a second side interlock at a second side of an adjacent like body. A second side interlock is provided at the second side of the body which is adapted to interlock with the first side interlock at a second end of an adjacent like body.
From these references, it will be seen that there is still a great need for a slim yet strong landing mat having high strength suitable for use as a temporary landing field for aircraft.